Integrated circuits typically have interconnect ports to communicate with other integrated circuits and other systems. Signals typically travel from an interconnect port on one integrated circuit, through a transmission medium, and to an interconnect port on another circuit or system to effect communications between the integrated circuits. Examples of transmission media include wires and traces within circuit boards, and cabling between circuit boards. As signal speeds increase, electrical signals suffer from attenuation in amplitude (voltage/current) and distortion in phase (time) as they travel through the transmission media. Signal rise and fall times at the receiver are slower than those sent at the transmitter. This can result in a smaller eye opening at the receiver.
FIG. 1 shows a prior art circuit assembly including circuit board 120, integrated circuit die 104, package 102, package substrate 106, heat sink 140, and off-board connection 130. As shown in FIG. 1, the electrical trace connecting integrated circuit die 104 to off-board connection 130 travels through the die-package boundary 108, package trace 109, package-board boundary 110, a long copper electrical trace 122 on circuit board 120 and then through jumper connection 132. In addition to attenuation, signals traveling on this path experience various discontinuities at die-package boundary 108, package-board boundary 110, and jumper connection 132. Due to skin effect loss in the various electrical traces, dielectric loss in the electrical medium, and the various discontinuities in the signal path, the signal gets distorted when traveling from integrated circuit die 104 to off-board connection 130. This distortion can take many forms, including but not limited to: attenuation, phase distortion, reflections, and delay.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternate integrated circuit interconnection techniques.